The Effect of Anoxia and Reoxygenation on the Production of Prostaglandin I2 from the Endothelial Cells of Umbilical Vein

ABSTRACT

The successful revascularization and reperfusion of ischemia are still associated with high systemic complication rates and severe local tissue injuries. The morality rates after revascularization have been reported to range from 10% to 20% and the amputation rates from 12% to 22%. It is well recognized that the microvasculature is highly sensitive to ischemia-reperfusion (I/R) and that the initial damage of endothelial cells contributes to I/R-induced tissue injury. In an effort to define the mechanisms responsible for reperfusion-induced vascular injury number of in vitro models have been developed to stimulate the responses of endothelial cells to I/R. Because of its simplicity, many investigators have used monolayers of cultured endothelial cells exposed to anoxia and reoxygenation as a model system to minic I/R-induced vascular changes in vivo. The endothelium serves as an important modulator of vascular homeostases by secreting various levels of both thrombotic and antithrombotic agents. One of the important product of endothelial cells, prostaglandin I2 or prostacyclin (PGI2) helps to maintain hemostasis through its involvement in coagulation, platelet activation, leukocyte migration and adhesion, vascular tone regulation and growth control. PGI2 synthesis is a readily quantifiable index of endothelial cell perturbation and thus serves as a marker for the identification of injurious stimuli. Endothelial cells were isolated from human umbilical vein and cultured in M-199 medium plus 20% fetal calf serum. Purity of culture was determined by immunological fluorescent staining of factor VIII related antigen, phase-contrast microscopy. TRK 790 radio-immunoassay kit was used for the measuring of 6-keto-PGF1 alpha released by endothelial cells. The results were as follows: 1) The concentration of PGI(2) released from the cultured endothelial cells was 33.44 +/- 2.26 pg/1 105 cells/mL 2) Incubation of endothelial cells with anoxia and reoxygenation resulted in PGI(2) release of 42.98 +/- 2.29 pg/1x10(5) cells/ml and 62.44 2.11 pg/1 105 cells/ml, respectively. 3) Incubation of endothelial cells with allopurinol (20 mumol/L) decreased the PGI(2) release to 40.68 +/- 2.99 pg/1x10(5) cells/ml. In conclusion, our data showed that the damage of endothelial cells in reoxygenotion group was significantly increased comparing anoxia group (p<0.005) and that allopurinol can inhibit reoxygenation-induced injury of endotheial cells.